An unusual subtype of meningioma: report of 3 cases of papillary meningioma and review of the literature

Background: Papillary meningioma is a rare subtype of meningioma most often occurs in young people. It usually shows aggressive growth pattern and was considered as tumor of WHO Ill which is different from the common meningioma. Case presentation: Here we report 3 cases of this rare subtype of meningioma in 2 males and a female, who are all adults. Grossly, the tumors had no clear boundary and showed invasive growth. Histologically, the tumor cells all formed the characteristic capillary-surrounding pseudo papillary structures. The tumors were mainly composed of epithelioid tumor cells with eosinophilic cytoplasm and pale-dyed nucleus with low mitotic index. The immunostaining showed that all the tumors have bidirectional differentiation of mesenchymal tissue and epithelium with positive EMA and vimentin staining. Ki67 index was relative high and about 10%45%. All the patients received tumor resection and 2 patients also received adjuvant radiotherapy. No recurrence occurred at 6-40 months follow-up. Conclusions: According to the findings, the 3 cases were diagnosed as papillary meningioma. We suggest that distinguishment of this rare type from the normal one, and timely surgery and adjuvant radiotherapy are critical for improving patients' outcomes. Close follow-up is necessary as recurrence is common in this rare subtype.